Methods for forming atomic layers and thin films including a tantalum amine derivative and devices including the same

ABSTRACT

Atomic layers can be formed by introducing a tantalum amine derivative reactant onto a substrate, wherein the tantalum amine derivative has a formula: Ta(NR 1 )(NR 2 R 3 ) 3 , wherein R 1 , R 2  and R 3  are each independently H or a C 1 -C 6  alkyl functional group, chemisorbing a portion of the reactant on the substrate, removing non-chemisorbed reactant from the substrate and introducing a reacting gas onto the substrate to form a solid material on the substrate. Thin films comprising tantalum nitride (TaN) are also provided.

RELATED APPLICATIONS

This application is a divisional of application Ser. No. 10/856,627,filed May 28, 2004, entitled Methods for Forming Atomic Layers and ThinFilms Including Tantalum Nitride and Devices Including the Same, whichapplication is a continuation-in-part of U.S. patent application Ser.No. 10/196,814, filed Jul. 17, 2002, which claims the benefit of KoreanPatent Application Nos. 2001-43526, filed Jul. 19, 2001 and 2002-17479,filed Mar. 29, 2002. This application also claims the benefit of KoreanPatent Application No. 2003-34352, filed May 29, 2003. The disclosuresof each are hereby incorporated herein by reference in their entirety asif set forth fully herein.

FIELD OF THE INVENTION

The present invention relates to methods of forming atomic layers andthin films, and more particularly, methods of forming atomic layers andthin films using metallic precursors.

BACKGROUND OF THE INVENTION

It is desirable for metal layers used for metal lines on semiconductordevices to be compatible in various structured forms. To increase thedensity of devices formed on a semiconductor substrate, a metal layercan be formed as a multi-layered structure. The metal layer can include,for example, aluminum or tungsten. However, the specific resistance ofaluminum is about 2.8×10E-8 Ωm and the specific resistance of tungstenis about 5.5×10 E-8 Ωm. Thus, aluminum and tungsten are typicallyunsuitable for a multi-layer structure. Consequently, copper, which hasrelatively low specific resistance and good electromigrationcharacteristics, is often used as a metal layer of a multi-layeredstructure.

Copper can exhibit a very high mobility when compared to silicon andsilicon oxide. However, copper can easily be oxidized when it reactswith silicon and silicon oxide. Accordingly, it may be desirable tosuppress the oxidization of copper by using a barrier metal layer.

A titanium nitride layer has been used as a barrier metal layer.However, the titanium nitride layer may not be suitable as a barriermetal layer for copper where the titanium nitride layer is desired tohave a thickness above 30 nm to restrain the mobility of copper. Sincethe titanium nitride layer has a resistance proportional to thethickness thereof and a high reactivity, the resistance may be highlyincreased when the titanium nitride layer has a thickness above 30 nm.

For at least this reason, a tantalum nitride layer is suggested for thebarrier metal layer where a tantalum nitride layer may restrain themobility of copper even when the tantalum nitride layer is thin and haslow resistance. Additionally, the tantalum nitride layer may exhibit asuitable step coverage characteristic and a suitable gap-fillingproperty so that the tantalum nitride layer can also be used as a metalplug, a metal wiring, a metal gate, a capacitor electrode and/or thelike, in addition to the barrier metal layer. Examples of tantalumnitride layers that can be used as barrier metal layers are disclosed inU.S. Pat. No. 6,204,204 (issued to Paranjpe et. al.), U.S. Pat. No.6,153,519 (issued to Jain et. al.), and U.S. Pat. No. 5,668,054 (issuedto Sun et. al.).

According to the disclosure in U.S. Pat. No. 5,668,054, the tantalumnitride layer is deposited through a chemical vapor deposition processby using terbutylimido-tris-diethylamido-tantalum ((NEt₂)₃Ta=Nbu^(t),hereinafter simply referred to as “TBTDET”) as a reactant. The processis carried out at a temperature above about 600° C. If the process iscarried out at a temperature of about 500° C., the specific resistanceof the tantalum nitride layer may exceed 10,000 Ωcm. In addition, sincethe above process is carried out at a relatively high temperature, thesemiconductor device can be thermally damaged. Further, it can bedifficult to achieve a tantalum nitride layer having the desired stepcoverage when a chemical vapor deposition process is used.

Recently, an atomic layer deposition (ALD) process has been suggested asa substitute for the chemical vapor deposition (CVD) process. The atomiclayer deposition process can be carried out at a relatively lowtemperature as compared with a conventional thin film forming processand can achieve superior step coverage. Examples of the atomic layerdeposition processes for depositing tantalum nitride are disclosed inU.S. Pat. No, 6,203,613 (issued to Gates) and in an article by Kang etal., entitled “Plasma-Enhanced Atomic Layer Deposition of TantalumNitrides Using, Hydrogen Radicals as a Reducing Agent,” Electrochemicaland Solid-State Letters, 4(4) C17-19 (2001). As described in the Kang etal. article, a tantalum nitride layer having a specific resistance ofabout 400 cm, can be formed by an atomic layer deposition process usingTBTDET. The deposition is carried out at a temperature of about 260° C.Accordingly, a thin film having a low specific resistance can be formedat a relatively low temperature. In addition, a hydrogen radicalobtained by a plasma-enhanced process is used as a reducing agent.Therefore, a power source is applied into a chamber when the depositionis carried out. For this reason, the process described by Kang et al.presents process parameters that may be influenced by the power sourceapplied to the chamber. Thus, while the Kang et al. process can be usedto form a thin film having a low specific resistance at a relatively lowtemperature, the process parameters, which include control of the powersource, are added. Moreover, because the Kang et al. process applies thepower source directly to a predetermined portion of the chamber to whicha semiconductor substrate is placed, the semiconductor substrate can bedamaged by the power source.

An ALD process using a tantalum chloride (TaCl₅) source in tantalumnitride (TaN) thin film deposition is disclosed in an article by MikkoRitala et al. entitled “Controlled Growth of TaN, Ta₃N₅ and TaOxNy ThinFilms by Atomic Layer Deposition,” Chem. Mater. 1999, 11, pp 1712-1218.Additionally, a CVD process using a TBTDET source in TaN thin filmdeposition is disclosed in an article by Tsai MH et al. entitled “Metalorganic chemical vapor deposition of Tantalum Nitride byTerbutyl-imidotris (Diethylamido) Tantalum for Advanced Metallization,”Applied Physics Letters, V. 67 N. 8, 19950821.

However, the conventional TaN deposition process can exhibit severalpotential problems due to the potential problems associated with thesources. For example, the TaCl₅ source is generally a halogen source,and the halogen source is a solid state and has a high melting point.Therefore, when the TaCl₅ source is employed for the deposition process,particles can be generated and impurities, including chloride, mayremain on the deposited TaN thin film which can induce additionalproblems. When a TBTDET source is used for the depositing process, thedeposition rate can be too slow because of a low vapor pressure.

Japanese Laid-Open Patent No. 2002-193981 discloses a method ofpreparing tertiary amyl imido-tris-dimethylamido tantalum(Ta(NC(CH₃)₂C₂H₅)(N(CH₃)₂)₃, (hereinafter simply referred to as“TAIMATA”) and a metal organic CVD (MOCVD) process using a solutionincluding TAIMATA as a precursor. According to the method disclosed inJapanese Laid-Open Patent No. 2002-193981, 1 mole of TaCl₅, 4 moles ofLiNMe₂ and 1 mole of LiNHtAm are reacted in an organic solvent at roomtemperature. The reaction product can be filtered and the solvent usedcan be removed to prepare TAIMATA. This material can be dissolved intoan organic solvent, such as hexane, and thus, the solution obtained canbe deposited onto a substrate in a CVD room to form a TaN thin film.

According to the above-described method, however, since the TaN thinfilm is formed by using only TAIMATA, the formation of the TaN thin filmmay be uncertain even though the preparation of TAIMATA may beadvantageously carried out. When the deposition process is carried outonto the substrate by the CVD process using only TAIMATA, the vaporpressure may not be high enough and the process can be ineffective.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide methods of forming atomiclayers including introducing a tantalum amine derivative reactant onto asubstrate, wherein the tantalum amine derivative has a formula:Ta(NR₁)(NR₂R₃)₃, wherein R₁, R₂ and R₃ are each independently H or aC₁-C₆ alkyl functional group, chemisorbing a portion of the reactant onthe substrate, removing non-chemisorbed reactant from the substrate andintroducing a reacting gas onto the substrate to form a solid materialon the substrate.

In other embodiments, the present invention provides methods of formingthin films including (a) introducing a tantalum amine derivativereactant onto a substrate, wherein the tantalum amine derivative has aformula: Ta(NR₁)(NR₂R₃), wherein, R₁, R₂ and R₃ are each independently Hor a C₁-C₆ alkyl functional group, (b) chemisorbing a portion of thereactant on the substrate, (c) removing non-chemisorbed reactant fromthe substrate, (d) introducing a reacting gas onto the substrate to forma solid material including tantalum nitride (TaN) on the substrate and(e) repeating steps (a) to (d) at least once to form a tantalum nitride(TaN) thin film including the solid material.

Further embodiments of the present invention provide methods of formingthin films including (a) forming an insulating layer on a substrateincluding therein an opening exposing a surface portion of thesubstrate, (b) introducing a tantalum amine derivative as a reactantonto the insulating layer having the opening, wherein the tantalum aminederivative has a formula: Ta(NR₁)(NR₂R₃), wherein R₁, R₂ and R₃ are eachindependently H or a C₁-C₆ alkyl functional group, (c) chemisorbing aportion of the reactant on the insulating layer having the opening, (d)removing non-chemisorbed reactant from the insulating layer having theopening, (e) introducing a reacting gas onto the substrate to form asolid material including tantalum nitride (TaN) on the substrate and (f)repeating steps (b) to (e) at least once to form a tantalum nitride(TaN) thin film on the insulating layer having the opening.

Embodiments of the present invention can further provide methods offorming thin films including mixing a tantalum amine derivative having aformula: Ta(NR₁)(NR₂R₃), wherein R₁, R₂ and R₃ are each independently Hor a C₁-C₆ alkyl functional group, with a reacting gas comprisinghydrogen (H₂), ammonia (NH₃), silane (SiH₄), disilane (Si₂H₆) or acombination thereof to form a mixture, and depositing the mixture on asubstrate.

In other embodiments, the present invention provides methods of formingthin films including forming an insulating layer on a substrateincluding therein an opening exposing a surface portion of the substrateand introducing a tantalum amine derivative as a reactant onto theinsulating layer having the opening with a reacting gas comprisinghydrogen (H₂), ammonia (NH₃), silane (SiH₄), disilane (Si₂H₆) orcombinations thereof to form a tantalum nitride (TaN) thin film, whereinthe tantalum amine derivative has a formula Ta(NR₁)(NR₂R₃), wherein R₁,R₂ and R₃ are each independently H or a C₁-C₆ alkyl functional group.

Additional embodiments of the present invention provide atomic layersand thin films formed by the methods provided herein. Furtherembodiments of the present invention provide semiconductor devicesincluding the atomic layers and thin films provided herein

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the present invention will becomemore apparent by describing in detail embodiments of the presentinvention with reference to the attached drawings in which:

FIGS. 1A to 1D present cross-sectional views that illustrate reactionsoccurring on a substrate in an atomic layer deposition (ALD) processaccording to some embodiments of the present invention;

FIG. 2 presents a graph showing vapor pressures according to temperaturefor terbutylimido-tris-diethylamido-tantalum (TBTDET) and tertiary amylimido-tris-dimethylamido tantalum (TAIMATA) used as a source whenforming a tantalum nitride (TaN) thin film according to some embodimentsof the present invention;

FIGS. 3A and 3B present the chemical formulas of TBTDET and TAIMATA usedas a source when forming a TaN thin film according to some embodimentsof the present invention;

FIGS. 4A and 4B present graphs illustrating deposition rates withrespect to temperature of a stage heater during deposition of TAIMATA bya chemical vapor deposition (CVD) process under an argon (Ar) atmosphereaccording to some embodiments of the present invention, wherein FIG. 4Ais illustrated with a uniformity and FIG. 4B is illustrated with aspecific resistance;

FIGS. 5A and 5B present graphs illustrating deposition rates withrespect to temperature of a stage heater during deposition of a TAIMATAsource by a CVD process while supplying an ammonia (NH₃) reacting gassimultaneously according to some embodiments of the present invention,wherein FIG. 5A is illustrated with a uniformity and FIG. 5B isillustrated with a specific resistance;

FIG. 5C presents a graph showing deposition rates with respect to theflowing amount of NH₃ during deposition of a TAIMATA source by a CVDprocess while supplying a NH₃ reacting gas simultaneously along with aspecific resistance according to some embodiments of the presentinvention;

FIG. 6A presents a graph showing deposition rates according to the NH₃dosage with changing temperature when depositing a TAIMATA source by anALD process while supplying a NH₃ reacting gas simultaneously accordingto some embodiments of the present invention;

FIG. 6B presents a graph showing deposition rates according to theTAIMATA dosage when depositing a TAIMATA source by an ALD process whilesupplying a NH₃ reacting gas simultaneously according to someembodiments of the present invention;

FIGS. 7A to 7C present cross-sectional views illustrating a method offorming a TaN thin film on an insulating layer having an openingaccording to some embodiments of the present invention; and

FIG. 8 presents a scanning electron microscope (SEM) picture showing aTaN thin film that is formed by an ALD process on an insulating layerhaving an opening that has a predetermined aspect ratio using a TAIMATAsource with a NH3 reacting gas according to some embodiments of thepresent invention.

DETAILED DESCRIPTION OF EMBODIMENTS ACCORDING TO THE INVENTION

The present invention will now be described more fully herein withreference to the accompanying drawings, in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as being limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete and will fully conveythe concept of the invention to those skilled in the art.

The terminology used in the description of the invention herein is forthe purpose of describing particular embodiments only and is notintended to be limiting of the invention. As used in the description ofthe embodiments of the invention and the appended claims, the singularforms “a”, “an” and “the” are intended to include the plural forms aswell, unless the context clearly indicates otherwise.

Unless otherwise defined, all terms, including technical and scientificterms used in the description of the invention, have the same meaning ascommonly understood by one of ordinary skill in the art to which thisinvention belongs. All publications, patent applications, patents, andother references mentioned herein are incorporated by reference in theirentirety.

It will be further understood that the terms “comprises” and/or“comprising,” when used in this specification, specify the presence ofstated features, steps, operations, elements, and/or components, but donot preclude the presence or addition of one or more other features,steps, operations, elements, components, and/or groups thereof.

Moreover, it will be understood that steps comprising the methodsprovided herein can be performed independently or at least two steps canbe combined. Additionally, steps comprising the methods provided herein,when performed independently or combined, can be performed at the sametemperature or at different temperatures without departing from theteachings of the present invention.

In the drawings, the thickness of layers and regions are exaggerated forclarity. It will also be understood that when a layer is referred to asbeing “on” another layer or substrate or a reactant is referred to asbeing introduced, exposed or feed “onto” another layer or substrate, itcan be directly on the other layer or substrate, or intervening layerscan also be present. However, when a layer, region or reactant isdescribed as being “directly on” or introduced, exposed or feed“directly onto” another layer or region, no intervening layers orregions are present. Additionally, like numbers refer to likecompositions or elements throughout.

As will be appreciated by one of skill in the art, the present inventionmay be embodied as compositions and devices as well as methods of makingand using such compositions and devices.

A method of forming an atomic layer and a thin film by using an organicmetal precursor or a tantalum halide precursor as a reacting materialhas been disclosed. According to methods disclosed in Korean Laid-OpenPatent No. 2003-0009093 published on Jan. 29, 2003 (corresponding toU.S. patent application Ser. No. 10/196,814, filed Jul. 17, 2002), agaseous phase reacting material is introduced into a chamber in which asubstrate is placed. The introduced material is deposited by an atomiclayer unit. An atomic layer including a metal element that has a lowspecific resistance at a relatively low temperature can beadvantageously formed. However, there continues to be a desire forimproved methods that require less complex process parameters.

In some embodiments of the present invention, methods of forming atomiclayers according to the present invention comprise, consist essentiallyof or consist of introducing a tantalum amine derivative reactant onto asubstrate, wherein the tantalum amine derivative has a formula:Ta(NR₁)(NR₂R₃)₃, wherein R₁, R₂ and R₃ are each independently H or aC₁-C₆ alkyl functional group, and thus, may be the same or differentfrom each other, chemisorbing a portion of the reactant on thesubstrate, removing non-chemisorbed reactant from the substrate andintroducing a reacting gas onto the substrate to form a solid materialon the substrate. In some embodiments, the methods are carried out by athermal atomic layer deposition (ALD) process or a radical assistedatomic layer deposition (RAALD) process using remote plasma. In fartherembodiments, the reactant can be provided in a liquid state. Inparticular embodiments, the reactant excludes a halogen component. Instill other embodiments, the tantalum amine derivative can comprisetertiary amyl imido-tris-dimethylamido tantalum(Ta(NC(CH₃)₂C₂H₅(N(CH₃)₂)₃). In still other embodiments, a portion ofthe reactant is chemisorbed on the substrate and the remaining part ofthe reactant is physisorbed on the substrate. The physisorbed reactantthat is the non-chemisorbed reactant can be removed using an inert gas.The inert gas can comprise argon (Ar), helium (He), nitrogen (N₂) or acombination thereof. In some embodiments, the reacting gas can comprisehydrogen (H₂), ammonia (NH₃), silane (SiH₄) disilane (Si₂H₆) or acombination thereof. The reacting gas can further comprise activatedhydrogen (H2), activated ammonia (NH₃), activated silane (SiH₄) oractivated disilane (Si₂H₆). Additionally, the activated reacting gas canbe obtained by a remote plasma process. In some embodiments, the solidmaterial formed can comprise tantalum nitride (TaN). In otherembodiments, a solid comprising TaN can be formed on the substrate byintroducing a reacting gas to remove a ligand-bonded element from thechemisorbed reactant. The ligand-bonded element can be removed using acompound that comprises H₂, NH₃, SiH₄ or Si₂H₆ or a combination thereofIn some embodiments, the compound can be activated by a remote plasmaprocess. Activation by a remote plasma process may prevent damage to thesubstrate. In some embodiments, the methods can be carried out at aconstant pressure in a range of about 0.3 Torr to about 30 Torr. Instill other embodiments, the methods can be carried out at a constantpressure in a range of about 0.01 Torr to about 10 Torr. In furtherembodiments, the methods can be carried out at a constant pressure in arange of about 0.01 Torr to about 5 Torr. Additionally, in someembodiments, the methods can be carried out at a temperature in a rangeof about 100° C. to about 550° C. In other embodiments, the methods canbe carried out at a temperature in a range of about 100° C. to about450° C. In still other embodiments, the methods can be carried out at atemperature in a range of about 100° C. to about 350° C.

Methods for depositing atomic layers will be described with reference tothe accompanying drawings. In particular, FIGS. 1A to 1D present crosssectional views illustrating methods of forming an atomic layer.Referring specifically to FIG. 1A, a substrate 10, such asmonocrystalline silicon, is placed in a process chamber 5. The chamber 5is then maintained at an appropriate pressure range and temperaturerange. Reactants 12 are introduced onto the substrate 10 placed withinthe chamber. As a result, the reactants 12 are chemisorbed on thesubstrate 10.

Referring to FIG. 1B, an inert gas is introduced onto the substrate tofacilitate purging. As a result, the non-chemisorbed reactants 12 areremoved from the substrate 10.

Referring to FIG. 1C, a reacting gas that comprises H₂, NH₃, SiH₄,Si₂H₆, or a combination thereof is introduced onto the substrate 10. Insome embodiments, the reacting gas is introduced after activating thereacting as using a remote plasma process.

Referring to FIG. 1D, at least some of the ligand-bonded elements 12 aincluded in the bonding elements of the chemisorbed reactants on thesubstrate 10 are removed by the reacting gas. The removal of theligand-bonded elements 12 a may be carried out by a ligand exchangebetween the ligand-bonded elements 12. The ligand-bonded elements areremoved by the reacting gas because the reactive force of the reactinggas with respect to the ligand-bonded elements is greater than thebonding force of the ligand-bonded elements with respect to thechemisorbed reactants. Additionally, since Ta═N is a double-bondedstructure, the bonding between Ta and N may not be affected by thereacting gas. Therefore, by removing the ligand-bonded elements, theatomic layer including Ta═N can be formed on the substrate. Thus, anatomic layer 14 comprising TaN is formed on the substrate 10.

Embodiments of the present invention further provide methods of formingthin films comprising, consisting essentially of or consisting ofintroducing a tantalum amine derivative reactant onto a substrate,wherein the tantalum amine derivative has a formula; Ta(NR₁)(NR₂R₃),wherein, R₁, R₂ and R₃ are each independently H or a C₁-C₆ alkylfunctional group and thus, may be the same or different from each other,chemisorbing a portion of the reactant on the substrate, removingnon-chemisorbed reactant from the substrate, introducing a reacting gasonto the substrate to form a solid material including tantalum nitride(TaN) on the substrate and repeating steps (a) to (d) at least once toform a tantalum nitride (TaN) thin film including the solid material. Insome embodiments, the steps can be repeated in sequence. In particularembodiments, the reactant excludes a halogen component. In otherembodiments, the tantalum amine derivative can comprise tertiary amylimido-tris-dimethylamido tantalum (Ta(NC(CH₃)₂C₂H₅(N(CH₃)₂)₃) (TAIMATA).The reacting gas can comprise hydrogen (H₂), ammonia (NH₃), silane(SH₄), disilane (Si₂H₆) or a combination thereof. The reacting gas canbe introduced with an inert gas that comprises Ar, He, N₂ orcombinations thereof Thus, the non-chemisorbed reactant can be removedusing an inert gas comprising Ar, He, N₂ or a combination thereof.Further, the reacting gas comprising H₂, NH₃, SiH₄, Si₂H₆ or acombination thereof can be activated using a remote plasma process.Moreover, forming layers in the methods of forming thin films can becarried out by a chemical vapor deposition (CVD) process, a thermal CVDprocess or a plasma enhanced CVD process. Additionally, the methods canbe carried out at a constant pressure in a range of about 0.3 Torr toabout 30 Torr. In still other embodiments, the methods can be carriedout at a constant pressure in a range of about 0.01 Torr to about 10Torr. In further embodiments, the methods can be carried out at aconstant pressure in a range of about 0.01 Torr to about 5 Torr.Additionally, in some embodiments, the methods can be carried out at atemperature in a range of about 100° C. to about 550° C. In otherembodiments, the methods can be carried out at a temperature in a rangeof about 100° C. to about 450° C. In still other embodiments, themethods can be carried out at a temperature in a range of about 100° C.to about 350° C.

As described in more detail with reference to the accompanying figures,methods of forming thin films according to the present inventionemploying an atomic layer deposition process can provide thin filmshaving a relatively low specific resistance while being formed at arelatively low temperature. In particular, when the reacting gas isactivated by a remote plasma process, a process parameter may beexcluded due to the generation of plasma. Thus, the process may becarried out at a low temperature. Additionally, a TaN thin film can beadvantageously formed by repeating the above-described atomic layerdeposition process. Moreover, experiments were performed to comparetantalum amine derivatives comprising TAIMATA and conventionally knowntantalum amine derivatives to confirm the suitability of TAIMATA. Suchexperiments were implemented with and without a reacting gas.

FIG. 2 presents a graph showing vapor pressures of the source forforming the TaN thin film, TBEDET and TAIMATA, according to temperature.In FIG. 2, the horizontal axis represents the temperature and thevertical axis represents the vapor pressure. FIG. 2 demonstrates thatthe vapor pressure of TAIMATA was higher than that of TBTDET at the sametemperature.

FIGS. 3A and 3B present the chemical formulae representing TBTDET andTAIMATA, which can be sources of forming a TaN thin film. FIG. 3Acorresponds to TBTDET and FIG. 3B corresponds to TAIMATA. Both compoundscan exclude any halogen elements such as chlorine, fluorine, bromine,and the like. However, the vapor pressure (Vp) of TBTDET is about 0.01Torr at a temperature of about 60° C. and the phase thereof is a liquidstate at room temperature. Alternatively, the vapor pressure (Vp) ofTAIMATA is about 0.1 Torr at a temperature of about 60° C. Therefore,the vapor pressure of TAIMATA is about 10 times greater than that ofTBTDET. In addition, the phase of TAIMATA is a solid state at roomtemperature. However, the melting point of TAIMATA is about 34° C.,which is below 40° C. Therefore, when TAIMATA is heated to about 40° C.,the phase of TAIMATA can be changed into a liquid state. Therefore, whenTAIMATA is used in a deposition process, the problem of particlegeneration may be solved through slight heating. To deposit TaN usingTAIMATA, various processes including CVD, PECVD, ALD, RAALD and the likeare applicable. Reacting gases for forming TaN can comprise NH₃, H₂,SiH₄, Si₂H₆, and the like.

To examine the depositing characteristic of TAIMATA, a TaN depositionexperiment was implemented by a CVD process under an Ar gas atmosphere.FIGS. 4A and 4B present graphs illustrating deposition rates accordingto the temperature of a stage heater during deposition of TAIMATA by aCVD process under the Ar gas atmosphere. FIG. 4A presents a graphshowing a deposition rate according to the temperature of the stageheater along with uniformity and FIG. 4B presents a graph showing adeposition rate according to the temperature of the stage heater alongwith a specific resistance.

Referring to FIG. 4A, curved line ‘a’ represents deposition rate andcurved line ‘b’ represents uniformity. TaN was deposited by the CVDprocess under the Ar atmosphere while the temperature of the stageheater was increased from about 100° C. to about 550° C. The depositionwas started when the temperature of the substrate was about 300° C. orMore. The deposition rate is directly proportional to an increase intemperature of the substrate. The decomposition temperature of TAIMATAconfirmed by the experiment was about 300° C. According to experimentsperformed at a temperature range between about 300° C. to about 550° C.,the deposition rate increased along with an increase of the depositiontemperature. However, TAIMATA was not saturated. Therefore, the resultssuggest that the deposition rate was dependent on a surface reaction inthe entire temperature range. In addition, the uniformity of the formedlayer was improved as the deposition temperature increased.

FIG. 4B illustrates the specific resistance of the formed TaN layermeasured by the above-described experiment. Curved line ‘a’ representsdeposition rate and curved line ‘c’ represents specific resistance.Specifically referring to FIG. 4B, the specific resistance of the TaNlayer formed by the CVD process without adding a reacting gas, was400,0000 Ωcm at a temperature of about 500° C., and 100,000 Ωcm at atemperature of about 550° C. The results suggest that the specificresistance decreased according to the increase of the depositiontemperature.

A deposition experiment was performed with a TAIMATA source along with areacting gas. The TaN layer was formed by the CVD process while addingNH₃ as the reacting gas. The results are presented in FIGS. 5A to 5C.More specifically, FIGS. 5A and 5B present graphs illustratingdeposition rates according to the temperature of a stage heater duringdeposition by the CVD process while applying a TAIMATA source along withNH₃ reacting gas. FIG. 5A presents a graph showing the deposition ratealong with uniformity and FIG. 5B presents a graph showing thedeposition rate along with a specific resistance.

FIG. 5C presents graphs showing a deposition rate with a specificresistance according to the flowing amount of NH₃ during deposition of aTAIMATA source with NH₃ reacting as by a CVD process.

Referring to FIG. 5A, the graph presenting the deposition rate as afunction of temperature is illustrated. Curved line ‘a’ represents thedeposition rate and curved line ‘b’ represents the uniformity. When TaNwas deposited while increasing the temperature of the stage heater fromabout 100° C. to about 550° C., the deposition started at about 150° C.The deposition started at a lower temperature below about 300° C., whichwas the starting temperature of the deposition of TAIMATA without addingthe reacting gas. The deposition rate increased within the temperaturerange of from about 150° C. to about 300° C. and the deposition rate wasconstant at the temperature range of from about 300° C. to about 550° C.This constant range is a mass transport regime. Based on theabove-described experiment, a window region of an ALD temperature by thereaction of TAIMATA and NH₃ can be obtained in the region of from about150° C. to about 300° C.

Referring to FIGS. 4A and 5A, the deposition rate at a temperature ofabout 300° C. was about 8.0 Å/min when using only TAIMATA, however, thedeposition rate at a temperature of about 300° C. was about 270 Å/minwhen using TAIMATA with NH₃. Thus, the deposition rate increased byabout 30 times when NH₃ was added as the reacting gas.

FIG. 5B presents results obtained after measuring the specificresistance of the TaN layer formed by the above-described experiment.Curved line ‘a’ represents the depositing rate and curved line ‘c’represents the specific resistance.

Referring to FIG. 5B, the specific resistance of the TaN thin filmformed by the CVD process using TAIMATA and NH₃ was 300,000 Ωcm at atemperature of about 400° C. The specific resistance rapidly decreasedat a temperature of above about 450° C. and reached about 8,000 Ωcm at atemperature of about 550° C. The results indicate that the specificresistance was greatly decreased as the depositing temperatureincreased.

FIG. 5C presents results obtained after measuring the deposition rateand the specific resistance according to the flowing amount of NH₃ bythe CVD process at about 500° C. In FIG. 5C, curved line ‘e’ representsthe deposition rate and curved line ‘f’ represents the specificresistance. The results indicate that the specific resistance decreasedfrom about 400,000 Ωcm to about 20,000 Ωcm as the flowing amount of NH₃increased.

A test of CVD-TaN deposition was performed using TAIMATA. Thedecomposition temperature of TAIMATA was at least about 300° C. and theALD window region was in the temperature range of about 150° C. to about300° C. The deposition characteristic of the ALD-TaN using TAIMATA andthe reacting gas in the ALD window region was measured, and the behaviorof the TaN deposition rate according to a dosage of NH₃ and TAIMATA wasexamined. The results are depicted in FIGS. 6A and 6B. Morespecifically, FIG. 6A presents graphs showing deposition rates accordingto dosage of NH₃ when deposition was performed by an ALD method whilesupplying a TAIMATA source with NH₃ reacting gas for several differenttemperatures.

FIG. 6B presents graphs showing deposition rate according to dosage ofTAIMATA when deposition was performed by an ALD method while supplying aTAIMATA source with NH₃ reacting gas. The dosage is obtained bymultiplying the partial pressure of the source and the pulsing time. Aunit of the dosage is Langmuir (1 Langmuir=1E-6 Torr-sec). The appliedTaN-ALD process is as follows. First, the gaseous phase TAIMATAprecursor was introduced onto a substrate as the reactants. Through theintroduction of the precursor, a portion of the reactants waschemisorbed on the substrate. An inert gas was then introduced onto thesubstrate to remove non-chemisorbed reactants from the substrate. One ofH₂, NH₃, SiH₄, Si₂H₆ or a combination thereof was introduced onto thesubstrate to remove ligand-bonded elements included in the chemisorbedreactants to form a solid material including TaN. Through repeating theabove-described steps at least once, and in some embodiments, insequence, a TaN thin film was formed from the solid material.

Referring to FIG. 6A, the graphs illustrate the deposition ratesaccording to the dosage of NH₃. Curved line ‘a’ corresponds to thetemperature of the stage heater of 200° C., curved line ‘b’ correspondsto the temperature of the stage heater of 250° C. and curved line ‘c’corresponds to the temperature of the stage heater of 300° C. The dosageof NH₃ was increased to about 8×10⁶ by increasing the pulsing time ofNH₃ at a temperature of about 200° C. The deposition rate increased whenthe dosage was below about 4×10⁶, however, the deposition rate rapidlydecreased when the dosage was above about 4×10⁶. When the temperature ofthe stage heater increased to about 250° C., the deposition rateincreased compared to the deposition rate at about 200° C. with the samedosage of NH₃. When additional experiments were performed by increasingthe temperature of the stage heater to about 300° C., the depositionrate also increased by the same manner.

Referring to FIG. 6B, the graphs present the deposition rate accordingto the dosage of TAIMATA. Curved line ‘a’ represents the depositing rateand curved line ‘b’ represents the uniformity. From FIG. 6B, it can benoted that the deposition rate increased according to the increase ofthe amount of TAIMATA. It can further be noted that saturation wasaccomplished when the dosage of TAIMATA was at least about 2×10⁴, whilesaturation is accomplished when the dosage of NH₃ is at least about4×10⁶.

Embodiments of the present invention further provide methods of formingthin films comprising, consisting essentially of or consisting of (a)forming an insulating layer on a substrate including therein an openingexposing a surface portion of the substrate, (b) introducing a tantalumamine derivative reactant onto the insulating layer having the opening,wherein the tantalum amine derivative has a formula; Ta(NR₁)(NR₂R₃),wherein R₁, R₂ and R₃ are each independently H or a C₁-C₆ alkylfunctional group and thus, may be the same or different from each other,(c) chemisorbing a portion of the reactant on the insulating layerhaving the opening, (d) removing non-chemisorbed reactant from theinsulating layer having the opening, (e) introducing a reacting gas ontothe substrate to form a solid material including tantalum nitride (TaN)on the substrate and (g) repeating steps (b) to (e) at least once toform a tantalum nitride (TaN) thin film on the insulating layer havingthe opening. In some embodiments, the steps are repeated in sequence. Inother embodiments, the tantalum amine derivative can comprise tertiaryamyl imido-tris-dimethylamido tantalum (Ta(NC(CH₃)₂C₂H₅(N(CH₃)₂)₃). Inparticular embodiments, the reactant excludes a halogen component. Instill other embodiments, the reacting gas can remove a ligand-bondedelement from the chemisorbed reactant. The reacting gas can comprise H₂,NH₃, SiH₄, Si₂H₆ or a combination thereof. In some embodiments, thenon-chemisorbed reactant is removed using an inert gas comprising Ar,He, N₂ or a combination thereof. In other embodiments, the opening has alarge aspect ratio. An aspect ratio of the opening can be at least about10:1. According to further embodiments of the present invention, thesemethods can be carried out at a temperature of about 100° C. to about350° C. Repeatedly carrying out the above-described integration process,a TaN thin film having a predetermined thickness can be formed. Thethickness of the thin film can vary according to the number of times thesteps are repeated. Therefore, the thickness of the thin film may becontrolled by adjusting the number of repetitions of the steps. Wherethe atomic layer integration method is utilized, a thin film having adesirable step coverage can be formed. Further, the TaN thin film can beadvantageously formed on a multi-layered structure formed on a substrateas well as the insulating layer pattern having the opening.

Embodiments of the present invention further provide methods of formingthin films comprising, consisting essentially of or consisting of mixinga tantalum amine derivative having a formula: Ta(NR₁)(NR₂R₃), whereinR₁, R₂ and R₃ are each independently H or a C₁-C₆ alkyl functional groupand thus, may be the same or different from each other, with a reactinggas comprising H₂, NH₃, SiH₄, Si₂H₆ or a combination thereof to form amixture, and depositing the mixture on a substrate. In some embodiments,the tantalum amine derivative can comprise tertiary amylimido-tris-dimethylamido tantalum (Ta(NC(CH₃)₂C₂H₅(N(CH₃)₂)₃). Inparticular embodiments, the reactant excludes a halogen component.

In other embodiments, depositing the mixture is performed by a chemicalvapor deposition (CVD) process, a thermal chemical vapor deposition(CVD) process or a plasma enhanced chemical vapor deposition (PECVD)process. In still other embodiments, an inert gas can be mixed with thetantalum amine derivative. The inert gas can comprise Ar, He, N₂ or acombination thereof. In some embodiments, the reacting gas can compriseactivated H₂, NH₃, SiH₄, Si₂H₆ or a combination thereof. The activatedreacting gas can be obtained by a remote plasma process. In otherembodiments, depositing the mixture can be carried out at a temperatureof about 100° C. to about 550° C. In still other embodiments, depositingthe mixture can be carried out at a temperature of about 150° C. toabout 300° C. In particular embodiments, the thin film can comprisetantalum nitride (TaN).

Embodiments of the present invention further provide methods of formingthin films comprising, consisting essentially of or consisting offorming an insulating layer on a substrate including therein an openingexposing a surface portion of the substrate and introducing a tantalumamine derivative as a reactant onto the insulating layer having theopening with a reacting gas comprising H₂, NH₃, SiH₄, Si₂H₆ orcombinations thereof to form a tantalum nitride (TaN) thin film, whereinthe tantalum amine derivative has a formula Ta(NR₁)(NR₂R₃), wherein R₁,R₂ and R₃ are each independently H or a C₁-C₆ alkyl functional group andthus, may be the same or different from each other. In particularembodiments, the reactant excludes a halogen component.

In some embodiments, an inert gas comprising Ar, He, N₂ or a combinationthereof can be additionally mixed with the reactant. In otherembodiments, an aspect ratio of the opening is at least about 10:1. Infurther embodiments, the methods are performed at a temperature of about100° C. to about 350° C.

Methods of forming TaN thin films according to some embodiments of thepresent invention are described in more detail with reference to theaccompanying figures. More specifically, FIGS. 7A to 7C presentcross-sectional views illustrating methods of forming TaN thin films onan insulating layer having an opening portion and on a substrate.Referring to FIG. 7A, an insulating layer 52 including oxide can beformed on a substrate 50 such as a silicon substrate used in asemiconductor process. Referring to FIG. 7B, a portion of the insulatinglayer 52 is etched by a photolithography process to form an insulatinglayer pattern 52 a including an opening having a predetermined aspectratio. Referring to FIG. 7C, a TaN thin film 54 is formed on theinsulating layer pattern 52 a including the opening by an ALD-TaNprocess or a CVD-TaN process.

FIG. 8 presents a scanning electron microscope (SEM) pictureillustrating step coverage of the TaN thin film formed by depositing aTAIMATA source with an NH₃ reacting gas on an insulating layer having anopening with a predetermined aspect ratio by an ALD process. As apurging gas, a gas mixed of 1000 standard cubic centimeters per second(sccm) of hydrogen and 500 sccm of Ar was used and 100 sccm of Ar gaswas used as a carrier gas of TAIMATA. The reacting gas, for example,NH₃, was injected at a flow rate of about 600 sccm. A thickness of botha top portion and a bottom portion of a contact hole was 250 Å, criticaldimension (CD) of the top portion of the contact hole was about 250 nm,and the height of step was about 25,000 Å. Therefore, the aspect ratioof the contact hole was about 10. The drawing suggests that the thinfilm exhibited a step coverage characteristic of near 100%.

A photograph illustrated in FIG. 8 corresponds to a photograph of thethin film formed by the ALD process. In order to compare characteristicsof the thin films formed by the ALD-TaN process and the CVD-TaN process,thin films having a substantially same thickness were formed on the sametarget. Components of the thin films were analyzed. The results areprovided in Table 1. TABLE 1 CVD-TaN ALD-TaN Ta(%) 31.9 36.2 N(%) 36.554.7 O(%) 24.8 5.6 C(%) 6.8 3.5 N/Ta 1.144 1.511

Table 1 shows that the impurity content of the thin film formed by theALD process was low. When a deposition process was implemented using aTAIMATA source as described above, a TaN thin film having a desirablestep coverage without particles could be formed with a high depositionrate.

Thin films may be formed by a process such as the CVD process or the ALDprocess. However, the thin film formed by the ALD process can exhibitsuperior characteristics.

Formation of thin films having desirable step coverage and a suitablegap-filling property can be accomplished by deposition processesaccording to embodiments of the present invention. In addition, thetantalum precursor used in some embodiments of the present invention canexclude halogen impurities and can be used in a liquid state. Therefore,the generation of particles in implementing the process may be reducedor prevented. Further, since vapor pressure of the precursor is higheven at a low temperature, the deposition rate can remain acceptable.Consequently, improvement of the productivity and/or increase of theyield can be provided.

While the present invention is described in detail herein and furtherdescribed with reference to the exemplary embodiments, it will beunderstood by those of ordinary skill in the art that variousmodifications, alternate constructions and equivalents may be employedwithout departing from the true spirit and scope of the presentinvention as defined by the following claims.

1. A method of forming a thin film comprising: mixing a tantalum aminederivative having a formula: Ta(NR₁)(NR₂R₃), wherein R₁, R₂ and R₃ areeach independently H or a C₁-C₆ alkyl functional group, with a reactinggas comprising hydrogen (H₂), ammonia (NH₃), silane (SiH₄), disilane(Si₂H₆) or a combination thereof to form a mixture; and depositing themixture on a substrate.
 2. The method of claim 1, wherein the tantalumamine derivative comprises tertiary amyl imido-tris-dimethylamidotantalum (Ta(NC(CH₃)₂C₂H₅(N(CH₃)₂)₃).
 3. The method of claim 1, whereinthe reactant excludes a halogen component.
 4. The method of claim 1,wherein depositing the mixture is performed by a chemical vapordeposition (CVD) process.
 5. The method of claim 1, wherein depositingthe mixture is performed by a thermal chemical vapor deposition (CVD)process or a plasma enhanced chemical vapor deposition (PECVD) process.6. The method of claim 1, wherein the method further comprises mixing aninert gas with the tantalum amine derivative.
 7. The method of claim 6,wherein the inert gas comprises argon (Ar), helium (He), nitrogen (N₂)or a combination thereof:
 8. The method of claim 1, wherein the reactinggas comprises activated hydrogen (H₂), activated ammonia (NH₃),activated silane (SiH₄), activated disilane (Si₂H₆) or a combinationthereof
 9. The method of claim 8, wherein the activated reacting gas isobtained by a remote plasma process.
 10. The method of claim 1, whereinthe thin film comprises a tantalum nitride (TaN).
 11. The method ofclaim 1, wherein depositing the mixture is carried out at a temperatureof about 100° C. to about 550° C.
 12. The method of claim 1, whereindepositing the mixture is carried out at a temperature of about 150° C.to about 300° C.
 13. A method of forming a thin film comprising formingan insulating layer on a substrate including therein an opening exposinga surface portion of the substrate; and introducing a tantalum aminederivative as a reactant onto the insulating layer having the openingwith a reacting gas comprising hydrogen (H₂), ammonia (NH₃), silane(SiH₄), disilane (Si₂H₆) or combinations thereof to form a tantalumnitride (TaN) thin film, wherein the tantalum amine derivative has aformula Ta(NR₁)(NR₂R₃), wherein R₁, R₂ and R₃ are each independently Hor a C₁-C₆ alkyl functional group.
 14. The method of claim 13, whereinthe reactant excludes a halogen component.
 15. The method of claim 13,wherein the method is performed at a temperature of about 100° C. toabout 350° C.
 16. The method of claim 13, wherein an inert gascomprising argon (Ar), helium (He), nitrogen (N₂) or a combinationthereof is additionally mixed with the reactant.
 17. The method of claim13, wherein an aspect ratio of the opening is above about 10:1.
 18. Anatomic layer formed by the method of claim
 1. 19. A thin film formed bythe method of claim
 1. 20. An atomic layer thin film formed by themethod of claim
 13. 21. A thin film formed by the method of claim 13.22. A semiconductor device comprising the thin film formed by the methodof claim 19.